AGRO 42 |
| In this study, the anion transporter (AT) blockers, 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS), 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), anthracene-9-carboxylic acid (9-AC), and indanyloxy acetic acid 94 (IAA-94), were tested for toxicity against larvae of the European corn borer (ECB), Ostrinia nubilalis (Hübner) using no-choice feeding bioassays. All the AT blockers significantly reduced larval weight at ≥ 12.5 ppm and larval survival at ≥ 25 ppm compared to control, when fed for 7 days on treated diet alone or fed for 7 days on treated diet and 14 days on untreated diet (P < 0.05). A significant decrease in midgut pH of fifth instar larvae fed for 3 hrs on the AT blockers treated diet at 12.5, 25, and 50 ppm was observed (P < 0.05). The existence of a positive correlation (r2 = 0.83-0.91) between larval weight and midgut pH suggests that reduction in midgut pH may be responsible for the AT blockers toxicity against ECB larvae. Studies of midgut chloride transport with 36Cl- isotope indicated that the AT blockers significantly reduced chloride transport into the midgut epithelium from lumen (P < 0.05). Results from this study indicate the potential use of the AT blockers in pest management and as possible leads for new insecticides. |
|
Agrochemical Education Awards For Graduate Student Travel
8:00 AM-11:00 AM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Agrochemicals |